The Analytical Core Shared Service provides state of the art instrumentation for mass spectrometry-based chemical and biochemical analyses and personnel to assist investigators in the design and application of analytical methods and the interpretation of data. The Analytical Core is supported both by the Arizona Cancer Center (ACC) and the Southwest Environmental Health Sciences Center (SWEHSC) core grants. The objectives of the Analytical Core are to aid ACC and SWEHSC investigators: . In the identification of unknown compounds, . In the development of mass spectrometry based analytical methods, and . In the design of experiments and interpretation of analytical data. The Analytical Core is directed by Daniel C. Liebler, Ph.D., Associate Professor of Pharmacology and Toxicology and staffed by Thomas D. McClure, Ph.D., facility manager and one research specialist each supported by the ACC and SWEHSC core grants. Instrumentation in the Analytical Core includes a Finnigan TSQ7000 triple quadrupole instrument with electrospray and atmospheric pressure chemical ionization for HPLC-MS and HPLC-MS-MS work. This instrument is capable of protein and peptide sequence analysis as well as the analysis of a wide variety of biomolecules and macromolecules. The Analytical Core also houses a Finnigan MD-800 bench- top GC-MS system and a Hewlett Packard 1050 diode array HPLC system for method development. All analytical work is done by appointment. There is no charge assessed to ACC and SWEHC investigators for method development, whereas a flat per-sample fee is charge to recover costs of instrument service contracts.